1. Field of the Invention
The present invention relates to a data storing medium, a data recording apparatus, a data recording method, a data reproducing apparatus, a data reproducing method, a data writing method for a storing medium, a data writing apparatus for a data storing medium, and a data reproducing method for a data storing medium. In particular, the present invention relates to a data storing medium for digital data, a data recording apparatus, a data recording method, a data reproducing apparatus, a data reproducing method, a data writing method for a data storing medium, a data writing apparatus for a data storing medium, and a data reproducing method for a data storing medium.
2. Description of the Related Art
In recent years, as large storage storing media, a DVD (Digital Versatile Disc or Digital Video Disc) video disc and a DVD-ROM disc that are optical discs are becoming common. In addition, a direct-read-after-write optical disc (hereinafter referred to as DVD-R (Rewritable) disc) and a rewritable DVD disc (hereinafter referred to as DVD-RW disc) that have the same storage capacity as a DVD video disc (4.7 GB per side) will be placed on the market in the near future.
In a DVD video disc and a DVD-ROM disc, data is recorded as pits formed thereon. In the case of a DVD-R disc, when a record laser beam is radiated to a dye film formed thereon, it is heated and denatured. As a result, a light absorption characteristic varies. Thus, when data is reproduced from the recorded portion, the reflectance thereof varies. On the other hand, a DVD-RW disc is a phase-change-type optical disc using a record film on which data is recorded. In the DVD-RW, when the record film is heated with a high power laser beam, the record film becomes an amorphous state in which reflectance is low. When the record film of the DVD-RW is heated with a low power laser beam, the record film is restored to the original crystal state in which reflectance is high. Thus, although the data recording methods differ in a DVD-ROM disc and a DVD-RW disc, their data reproducing methods are the same in that data is reproduced corresponding to the variation of the amount of reflected light of the laser beam.
Thus, in a DVD-R disc and a DVD-RW disc, data can be reproduced therefrom with a DVD video player. This characteristic will result in an illegal copy of data recorded thereon. Most of DVD video software titles that are placed on the market are copy-prohibited software titles. When a copy prohibition bit of such a disc is turned on, the copy of the data is prohibited from being copied so as to protect the copyright of the data. However, if an illegal process is performed (for example, the copy prohibition bit is skipped), data recorded on a copy-prohibited disc can be copied.
In addition, in the case of a DVD video disc, a copy-prohibited video software title such as a movie is encrypted corresponding to a particular method such as CSS (Contents Scramble System). In other words, only an authorized software maker can produce software titles. In addition, only an authorized hardware device can reproduce such a software title. To decrypt encrypted data, copyright control information such as a key is recorded in a predetermined area of a DVD video disc.
When encrypted data cannot be decrypted, the copyright of a software title can be protected against such an illegal process (for example, the copy prohibition bit is skipped). However, when the copyright control information is copied along with encrypted data, since the encrypted data can be decrypted, the copyright of the software title cannot be protected. As a method for protecting the copyright control information from being copied, an area for a block that contains the copyright control information of a recordable disc, a DVD-RW disc, and a DVD-R disc may be record-prohibited. In other words, when an (n+2)-th sector is an area to which the copyright control information is written, as shown in FIG. 1, an area to which an error correction block containing the (n+2)-th sector is written is embossed. Thus, when the area is embossed, the copyright control information cannot be recorded. Since the entire block is embossed, the copyright control information cannot be decrypted with error correction code.
However, in the method shown in FIG. 1, since error data succeeds, reproduced data cannot be synchronized (frames cannot be synchronized). Thus, an abnormal process may take place (for example, the reproducing operation may stop). In addition, control data that is required to reproduce contents data may not be reproduced. Thus, the contents data cannot be reproduced from the disc with a conventional DVD video player. Thus, even if encoded data cannot be reproduced for copyright protection, data that is not copyright-protected and that has not been encrypted (for example, a broadcast program, a picture photographed by a video camera, and so forth) cannot be reproduced from a DVD-RW disc and a DVD-R disc with a DVD video player. The absence of the reproduction compatibility causes the usability of a DVD-RW disc and a DVD-R disc to deteriorate.